Glassy Winged Sharpshooter

The effects of the Glassy Winged Sharpshooter on Vineyards

The insect can eat 10 times its body weight per hour. It begins carrying Pierces Disease after eating a plant infected with the Xylella fastidiosa bacterium. The sharpshooter is also a threat to other agricultural products.

Pierces Disease was identified in California Wine Country over 100 years ago. But for years it was only spread by the slow moving blue green sharpshooter. In 1990, the robust glassy winged sharpshooter was discovered in California for the first time.

Originating in Ventura County, it spread like wild fire through Temecula. In 2004, glassy winged sharpshooters were found along Highway 80 in Vacaville, about 40 miles from Napa. Experts believe sharpshooters hitch-hike from infected areas in the wheel wells of vehicles, and then subsist in vegetation along freeways.

When eggs are found, they are sprayed and destroyed. Solano County agricultural officials have also unleashed a natural predator along the Highway 80 corridor. Miniscule wasps eat the egg clusters of the sharpshooter, and will hopefully eradicate the pest before it moves west into wine country. All plants entering Napa and Sonoma Counties are inspected for the pest.

At the same time, the wine industry is evaluating other measures to combat the glassy winged sharpshooter. When asked about this issue, Dale Brown, president of the Napa Valley Grape Growers Association, stated that, “Genetic resistance is where we want to go.” However, anything that has to do with genetic splicing is strictly regulated by the EPA.